Mobile telephony

ISSC can link a mobile phone to the University telephone network through a Corporate Net connection, as a result of which it will offer a functionality that is equivalent to the fixed phones within the University. The mobile subscriptions which are offered by the University are T-Mobile subscriptions. 


  • Processing applications for new mobile Corporate Net connections
  • Implementing software mutations (setting or changing shortened numbers and changing the traffic class)
  • Providing (additional) information regarding the costs of phone calls made from a specific telephone number
  • Purchasing and repairing mobile telephones
  • Calling from a fixed to a mobile number using 90xxxx
  • Redirecting phone calls between mobile and fixed telephone numbers using the standard function *21

Applying for/ending a subscription

You can apply for a mobile device with the standard hardware application form.

You can apply for a subscription with the 
mobile subscription application form.

Only applications submitted by telephone coordinators of University units and/or affiliated institutions can be processed. An up-to-date list of Telephone Coordinators can be found here.

This application (or termination) can be sent by the telephone co-ordinator to the following address:

Universiteit Leiden / ISSC

T.a.v. Tina Titahena

Postbus 9512

2300 RA Leiden

Or by e-mail to:

Subscription options

The options listed below can be ordered through ISSC:

  • Separate telephone subscription
  • Separate mobile telephone
  • Subscription including a mobile telephone
  • The mobile connections can be assigned to different traffic classes

Traffic classes:
Bronze: calling internal University numbers (fixed and mobile)
Silver: calling numbers in the Netherlands (national)
Gold: calling from and to other countries (national + international)

Bronze and Silver can also be reached abroad, at additional cost.

Other information

Please find below useful information with respect to mobile subscriptions.

Internet Europe
Can be useful and cheaper for those who go abroad on a regular basis.
Offers a fixed package and remains valid for the entire duration of the contract, and cannot be changed on a yearly basis or be cancelled in between.
When the package is exceeded the speed is reduced to 64/64 Kbps.
If the data limit is exceeded, the original speed is restored at the beginning of the new month.

Travel & Surf
Can be useful for those who make occasional trips abroad.
The use abroad is set per day and rounded up to 200KB or a multiple thereof. When purchasing an internet card, the internet volume on the day card is small and the day card is only valid for 24 hours. The internet volume of the week card is valid for 7 days after purchase. Potential remaining internet volume will expire at the end of this period. After
100MB, the speed automatically changes to maximum 64/64Kbps. In order to increase the speed, you have to buy a new card.
To activate the card, see the relevant .pdf documents.

Internet Europe / Travel & Surf
It is not possible to activate both options. You have to choose one or the other.
We advise you to apply some time before you leave.
Internet speed on the foreign network will depend on local availability.

Data package
Your use abroad will be set per day and rounded up to 200 KB or a multiple thereof.
You can have your data limit extended by means of a written confirmation from your supervisor or budget holder. Send an e-mail to helpdesk@issc.leidenuniv.nlor call +3171527(6906)

Mobile internet use abroad
As a T-mobile client, you are automatically given a limit in order to avoid unexpectedly high costs of mobile internet use abroad (through your telephone or laptop). For the EU countries (zone 1) there is a monthly limit, and for other countries (zone 2 and 3) a daily limit.

As of 1 July 2012 there is a monthly limit of € 59.50 for all internet use, including your use outside of Europe. You will receive an SMS message as soon as you have (almost) reached your limit. The daily limit of € 50.00 for zone 2 and 3 will expire as of 1 July 2012 due to the compulsory monthly limit of € 59.50 for all zones.


Problems should be reported to the client service of T-Mobile. You can also do this online through your My T-Mobile account.

Tel: 0800-7112 (free number)
From abroad: +31624007112

Opening hours: 08 am to 8 pm (Mon to Sat)

Specifications and questions

For specifications regarding the subscriptions, you can send your questions by e-mail to
You can also use the above address or the ISSC Helpdesk for requesting new PIN/PUK codes. 

Last Modified: 23-03-2017